It would probably be way easier and way less expensive to use faux fur. I see using a real pelt for something like the Stark's cloaks, but a huge mascot costume really isn't going to look better that way (and in fact might be worse off).

Head over to the "Sewing" or "General Construction" forum to ask this and/or search for "faux fur" on here and in Google. You'll likely find something suitable fairly quickly.